MSX Mascot?

Not AFAIK, but some gaming companies did, like konami that used penguins a lot.

I found it:

Source:
https://since1983.msx35th.technology/posts/3947869/

"The MSX mascot that has been around since that time.
He was commonly known as "MSX Boy", but his real name is still a mystery."

Wow really, never actually seen that fellow but it's a nice cute one

There are modern mascots like MSX-DOS-tan and I believe a whole slew of other tan’s.

Also in ads I’ve seen Panasonic use Ashguine as a mascot and National use King Kong (both Matsushita brands).

Screenshot at the top is Gun Fish. Middle left is Ladra's Legend. At the bottom is Puzzle Tower which was submitted to MSX Magazine Software Contest but was disqualified. So were Personal Finance Software and It's Pretending to be Flying on page 161.